Week 4 Flashcards
what is critical appraisal?
- appraises research for its strengths, limitations, and value for practice
what is the first step in the critical appraisal of QNR
- determining match between the clinical question and research design
ex. should it be QL or QN
the critical appraisal process for QN focuses on 3 broad questions:
- are the results of the study valid (validity)
- what are the results? (reliability)
- will the results help me in caring for my pts ? (applicability)
what is study bias (2)
- anything that distorts study findings in a systematic way arising from the methodology of the study
- something consistently occurring that could distort the outcomes & compromise the validity of the findings
ex. instrumentation that isnt valid or reliable, or confounding or extraneous variables
what is internal validity (3)
- anything that happens within the study that confounds our understanding of the relationship between the IV and DV
- what is the strength of the evidence that the IV rather than extraneous, confounding variables , or the instruments used caused the outcome
- the extent to which it is possible to make inference that the IV truly caused/influenced the DV
what is external validity (2)
- what is the strength of evidence that observed relationships are generalizable across people, settings, and time?
- being able ton generalize findings to population outside of the study
what is study validity
- refers to whether the study results can be believed (internal validity) and whether the results can be generalized to other settings/pt populations (external validity)
what is instrument validity (2)
- refers to whether the study measurements are measuring what they are supposed to be measuring
- can serve as a threat to internal study validity
what is study reliability (2)
- refers to the repeatability of the study
- if the study were repeated under the same circumstances, would the results be the same?
what is instrument reliability
- refers to the consistency of the instruments
- will the instruments yield the same results under the same conditions?
what can we ask to assess internal validity? (2)
- did the IV truly influence the DV?
- what competing explanation could there be for the results of the study?
what can help control internal validity (2)
- be aware of confounding variables
- instrument tools
what are 8 threats to internal validity
- history
- mortality
- selection
- maturation
- knowledge of who receives the intervention
- recall bias
- loss to follow up
- contamination
describe the history threat to internal validity
- other events co-occurring with casual factor that could also affect outcomes
- any other event that may occur along the same time as the IV is being measured in realation to its impact on the outcome
describe the mortality threat to internal validity
- differential loss of participants from different groups
- drop out of study
= attrition bias
describe the selection threat to internal validity
- ## biases arising from preexisting differences between groups being compared
what is the single biggest threat to studies that do not use an experimental design
- selection
how can selection bias be addressed/prevented? (2)
- randomization
- imp to test demographic differences that could impact the outcome
describe the maturation threat to internal validity
- processes that result simply from the passage of time
ex. natural wound healing is expected to occur with or without intervention
describe knowledge of who receives the intervention r/t internal validity
- can occur if subjects or those measuring outcomes know subject group assignment
- may cause the participants to be more motivated to help the researcher get a positive response
= performance bias
how can performance bias be reduced
- by blinding
describe recall bias
- can occur when subjects are asked to recall past actions or events (such as in case-control studies)
- subjects may give answers that are socially acceptable or what they “think” is what happened (may not remember correctly)
describe recall bias
- can occur when subjects are asked to recall past actions or events (such as in case-control studies)
- subjects may give answers that are socially acceptable or what they “think” is what happened (may not remember correctly)
describe how loss to follow up can be a threat to internal validity
- attrition could occur due to unforeseen side effects of the intervention or burdensome data collection procedures, leading to noncomparable groups
describe the contamination threat to internal validity
- can occur if intervention & control groups have interaction and info is shared, especially if the intervention is educational in nature
how can contamination be prevented
- implement the intervention to 1 group at a different time period
what is the type of bias that occurs because the subject gets better at something due to the passing of time
- maturation threat
what is the testing effect
- occurs when you give a knowledge survey, and give it to the same individual multiple times after an education intervention
- the individual then starts to learn (memorize) what the right answer is
external validity is about…
- generalizability
define generalizability
- the extent to which study findings can be applied to other groups & settings, and wider population that is similar to the study group
- dependant on reliability and validity of study procedures
what are some threats to external validity (2)
- inadequate sampling of study participants (if too small, may say theres no diff when there actyally is)
- unfortunately, enhancing internal validity can have adverse effects on external validity (more controls = behavior/context more artificial)
what are some preliminary questions to ask prior to critical appraisal of quantitative studies (7)
- why was the study done?
- what is the sample size?
- are the measurements of major variables valis and reliable?
- how was the data analyzed?
- were there any untoward events during the conduct of the study?
- how do the results fit w previous research in the area?
- what does this research mean for clinical practice?
what are the main concerns r/t reliability of a study (2)
- size of the intervention’s effect (effect size)
- precision in effect measurement (CI)
what are the main concerns for the applicability of a study
- will the study findings help me to care for my pts?
